Solvent-extraction process and apparatus



SOLVENT-EXTRACTION PROCESS AND APPARATUS v EiledAug. 12. 1959, s Sheets-Sheet 1 "DE PURE E T/mama MA TEE/4L LE -HM; Sta-non Sou-yaw SrbRAGE 1563 Pump INVENTOR McHELE BONO'TTO Feb; 17, 1942. M. BONOTTO 2,

SOLVENT-EXTRACTION PROCESS AND APPARATUS Filed Aug. 12, 1939 3 Sheets-Sheet 2 Sousur Wm 5 j I a nu "n 0 Q9 I i ikfii 40 41 v 48 i x i 44. 52' t MATERIAL INLET v :1 a T? 1 names 55 M y FUR: SOLVENT 56' CONDENSOR DIRECTION OF SOLVENT INLET QIREC IUN OFLIATERML Tb STILL DRYER INVENTOR Mane-LE Bolvorro T5 FILTER Sear/0N 0 MATERIAL M/scam Feb. 17, 1942.

Cbweme L 10 UID LEVEL M. BONOTTO 2, 273,557

Filed Aug. 12, 1 939 I 59. Puke 62 Genomes! 67 DRYER MATEnAL EXTRACTEDMATH'RIAL TQBE Exmacrsn 6 71 COLUMN LIGUIDLEVEL (5% IISGELLA 1b DIsTILLER 72 72 --EXTRACTOR 6a INVENTOR MCI-{5L5 BONOTT'O ATTORNEY I I Patented Feb. 17, 1942 j j UNITEDHV'WSTAT s PATENT OFFICE SOLVENT-EXTRACTION rnocnss AND .7 APPARATUS Michele Bonotto, Evansville, Ind., assignor to Extractol Process, Ltd., Wilmington, Del., a

corporation of Delaware Application August 12, 1939, Serial No. ga a-191 e -11 Claims. (01.202-339) I"his invention relates to improvements in solvent-'extraction processes and apparatus, and

I more particularly to processesand apparatus for the solvent-extraction of oil from oil-bearing materials, e I V Heretofore, solvent-extraction ,processes have generally been carried out, by passing or'moving, eitherby-gravit'y or mechanical apparatus, a body or column of solid oil-bearing material through tank of large diameter and subjecting such body or column to a liquid solvent moving in counter-- current to thematerial through the entire body or column of material in the tank. Also, extrac tion has been carried out .in a series of separate tubularconveyors arranged in inclined position by passing solvent in counter-current successively through each conveyor, but so far ,as I am aware; extraction has not been carriedout by subjecting, in a single continuous conveyor, '2.

long column of solid material to a series of separate counter-current extraction operations, such as hereinafter described.- I

I have found that counter-currentextraction means forcausing or permitting [the solvent to ,percolate atsuitable intervals through the sides of the conduit-conveyor and thernoving column of material tobe, extracted therein and applying successively such percolated solvent to other parts of. themoving column-0r body ofmaterial. I

have found that diffusion also'may 'be accoming and diffusion in counter-current 'a plurality of 'times during conveyance through a single unit andpreferably to subject to counter-current extraction a relatively long'and narrow column of such material by alternate leaching and diffusion during conveyance thereof through a conveyorconduit.

Another, object of my invention is to enable such alternate leaching and difiusion operations to'be carried out in a conventional conveyor during movement of the, material and solvent'in counter-current relationship.

Another object of my invention is to produce, an extraction unit by utilizing a conventional conveyor-conduit having suitable liquid-passing conveyor elements by providing therein a plurality or series of imperforate portions arranged alplished in such a conveyor and thatthe process may thuscomprisealternat stageslof difiusion and'leaching. One of the objects of my invention is to enable the efficient extraction of oil or other soluble in- 'gredients from material bearing such ingredients by, the novel method of subjecting a column or body of such material in a, single conduit to extraction by the alternate longitudinal passing of the solvent and the percolation thereof through the sides and preferably the provision in asingle and one perforate section for percolating such solvent through the sides of the conveyor-conduit. fAnotherobJ'ectof my inventionis to enable 1 the, material to be subjected to alternate leachternately with a plurality or series of perforated or screened portions surrounded by collecting or draining boxes, feeding solid material to be extracted to said conduit, conveying such material through. said conduit including such screened sections, and subjecting such material to extraction by passing solvent through imperforate portions of said conduit anddraining such solvent through said perforated portions.

Another object of my invention is to subject the quantity passing through said perforate pore tions into said draining boxes Another object of my invention is to produce an-extraction unit by providing, in a conveyorconduit at varying levels, groups of such alternate imperforate and perforate portions whereby 'solventapplied and enriched from material passing through one group may be reapplied to material in another group which. is passing through a difierent stage of extraction. Another object of my invention is to produce, in an alternately perforate and imperforate conduit of the tape specified, a counter-current extraction unit by providing a plurality of such groups, applying and enriching fresh solvent in a group adjacent to the material outlet, draining such solvent and again applying such enriched solvent to a group closer to the material inlet or feed hopper.

Another object of my invention is to provide, along the length of a single conduit, a series of groups of such alternate'perforate andimperforate portions, comprising a fresh-solvent group, a weakmiscella group, and a strong-miscella with the conveyor shown in Fig. 3;

fresh solvent group to the weak-miscella group and to apply the miscella drained from the weakmiscella group to the strong-miscella group.

Another object of my invention is to filter and simultaneously further enrich the strong miscella by filtering such strong miscella through fresh flaked material to deposit the fines from the miscella in the material and to remove and carry away in the filtrate free oil from such flaked material.

Another object of my invention is to produce an extraction unit by utilizing a conveyor conduit of sufiicient length and providing therein a series of extraction groups, each embodying a plurality of cooperating section pairs, comprising a diffusion section composed of an imperforate conduit portion of given length and a leaching section also of given length composed of a perforate portion' surrounded by a draining box, and providing conduits for solvent connected to inlets in the imperforate sections above'said draining box, and

applying through said conduits liquid solvent at act and co-operate with each other in the performance of the functions and the accomplishment of the results herein contemplated, and comprises in one of its adaptations the species or preferred formillustrated in the accompanying drawings, in which: a V Fig. 1 is a view in side elevation ofextraction apparatus embodying my invention;

Fig. 2 is a section on the line 2-2 of Fig. 1, looking in thedirection of the arrows;

' Fig. 3 is a view in perspective of a modified form of conveyor employed in extraction apparatus embodying my invention;

Fig. 4 is an'illustrative diagrammatic view showing the pipes and tanks used in connection Fig. 5. is still another modified form of my invention in which my conveyor extraction unit is employed in combination with an extraction column or tank.

Referring now to these drawings, I have illustrated three forms or types of apparatus suitable for carrying out my invention. Thus, in Figs, 1 and 2 I have illustrated a vertically-disposed flight-type conveyor having a materialincoming flight, an intermediate inclined flight and a material-outgoing flight. The incoming flight, as shown, comprises a vertical descending leg while th intermediate and outgoing flights comprise two upwardly and oppositely-inclined legs; in Figs. 3 and 4 I have shown a horizontally-disposed conveyor of rectangular conformation having incoming and outgoing flights and two intermediate flights which comprise four connected conveyor legs and in Fig. 5, I have shown a vertically disposed conveyor trapezoid-shaped in conformation having an incoming'horizontal leg, an intermediate outwardly-inclined leg, an inwardly-inclined outgoing leg and a materialfree descending leg which connects with the incoming horizontal leg which is fed from a column or tank such as described in my patents numbered 2,156,236 and 2,158,782.

' Referring now particularly to Figs. 1 and 2 of these drawings, which constitute th preferred ill group, and to apply the liquid drained from the form of mechanical apparatus for carrying out my invention, l indicates a. vertically-disposed conveyor-conduit, triangular in elevation, which may embody any suitable type of material-conveying mechanism but preferably comprises a conveyor of the flight or drag-chain type. In the said preferred form of my invention, a conduit conveyor apparatus of generally-conventional construction has a casing I which is suitably supported in conventional manner by members l' A descending leg 2 constitutes the incoming flight and is connected and communicates withan intermediate upwardly and outwardlyinclined leg or flight 3 which is connected and communicates with an outgoing flight 3' extending in upwardly-inclined, inwardly-disposed position and connected and communicating with the descending flight 2. This conveying mechanism thus comprises a continuous system of chain conveyor elements 4 connected-together by chains 4 and moved by drive wheel 5 driven by shaft 5' in conventional manner from any suitable source of power not shown.

The casing l is composed of a series of portions connected together to provide liquid and vapor tight joints.

In said preferred form of apparatus, I provide, in'each of the legs of the apparatus, an extraction group of alternate imperforate portions 1 and perforate portions 8 comprising a fresh solvent extraction group 9 positioned in the inclined material-outgoing leg, a used solvent group ID in the intermediate inclined leg and a weak-miscella group II in the vertical material-incoming leg. Each of these groups contains a plurality or series of such imperforate and perforate portions, and in the preferred form of my process, each imperforate portion is provided with a liquid inlet conduit I2 and each perforate portion embodies a screen-wall portion [3 which is arranged flush with the casing l and I has surrounding said screen-wall portion an outside jacket l4 spaced from the screen-wall portion to provide a drain box between the said screen portion and'said outside jacket.

In the preferred form of my invention, I preferably maintain the imperforate portion completely fill-ed with solvent liquid so as to provide a diffusion section within the same, and these imperforate diffusion sections are alternated with leaching sections which comprise the screenwall portions. The diffusion section may be kept full of liquid by applying through the inlet-conduits liquid solvent (comprising either pure solvent or used solvent which may be either stron or weak miscella or mixture) at, a quantity or pressure regulated in accordance with the drainage through the screened leaching sections to keep the said diffusion section full of liquid and thus to enable a diffusing action to take place therein.

It will be understood that in oleaginous or oilbearing materials, such as cotton seed, soya beans, tung nuts, linseed, castor beans, copra, bon meal. meat scraps and the like, the oil constituents are contained in cells and the cells are surrounded by membranes or tissues and it has been found that when these oil-bearing materials are subjected to the action of a suitable solvent or difperature rnaintained.

branes 'willzact like osmotic diaphragms tolpermit the osmoticdischarge of the soluble constituents from the cells and in either case ,en-

' abling the extraction of-the solubleconstituents from the cells and enabling osmotic dischargeor diffusion and consequent extraction of the soluble constituents from the cells.

' -In order tovpromote the osmotic discharge or diffusion of. soluble constituents through such membranes to the best possible advantage, the .diffusionagent or solvent employed should be preferably applied to the material in countercurrent, i. e., fresh solvent or diflusion agent hav- :ing maximum strength should be applied to outgoing material from which a part of the solubles has theretofore been extracted and used solvent or diffusion agent of less strengthsho'uld, be apdiffusion agent or solvent should be thoroughly intermingled; and. kept in intimate contact with I' l .the mass of material fora time period sufiicient l to enable such osmotic action or diffusionjtotake {place as -distinguished. from a mere washing operation. The determination of the length or du- [ration of this time period will dependupon the type of material being treated; the condition of such material, the strength of the diffusion agent orsolvent and other factors, suchas the tem- In the instant apparatus, itwillbe desirable;

' asv hereinabove stated, to maintain the imper forate portion or diffusing section full of the,

diffusing.agentorjsolvent and by so filling such imperforate section and then draining the solvent through a perforateleaching section below and conducted through inletpipe portion 12 to imperforate diffusion sections of group lllwhere further extraction, operations of alternate'diffusion and leaching take place. The used solvent 'from group In which has ,now become a mixture which Iv have termed ,fweak miscella is drained through, screens l3; :jackets l4 and pipes I2 [2 and lzfto'a weakfmiscella tank I! fromwhich it is pumped byppump through pipe 2|, heater 22 and pipe 2|. to and through inlet conduits IZ co'nnected to the imperforate diffusion sections of group II which is located in thedescending conveyorl'eg 'l' where fresh plied to the fresh or incoming material and the enrichment in oil through cessive steps.

materialin this incoming leg of the conveyor cpnduit is subjected to the solvent actionof relatively weak miscella. v v The division of the process in. three stages or groups 9, I0 and II is arbitrary and used only to] better describe the apparatus. There is no such division in practical 'operationbecause the pure solvent becomesstrong miscellaby gradual ;Durin'g-lpassage through groupil therela- 1 tively weak miscella is further enriched with oil and is drained throughscreens l3, Jackets Mend 'pipes 12 and, I2 to atank which I shallterm a, strong fmiscella tank 23.

'Thestrong miscella. thus produced contains impurities in the form of'particles of solids and the diffusing. section I am enabled, in a conveyor I apparatusor conduit, to provide for a seriesuof alternatevdiifusions inthe imperforate sections ing with each other'in pairs.

,I am enabled to produce counter-current relationship; between the solvent liquid and the andyleachings in the perforate sections, such diffusion and leaching sections thus cooperat in the preferred form of apparatus shown in Figs. 1 and 2,. I filter this strongmiscella, through fresh materialadjacent to thefe ed of the ma terial' by pumping this miscellaby Dump 24 and conducting same by pipe 25 through a filter section26, comprising an imperforate section 21 having a liquidinletl'l' and draining sections 28 m'aterialbyapplying pure or fresh solvent having a maximum strength to the material pass-' ing through the extraction group!) in the outgoingieg of the conveyor, then draining the relativelyrstrong used solvent from this extraction roup through screens l3 into the draining boxes'or jackets l4 and conducting this relatively-strong used solvent through pipe-portions l2 andapplying it through inletpipes 12 to the ,in- I termediate extraction group I0, then draining the'twice fused solvent from this intermediate 1 group which has become what I shall term relatively weak miscella,- and applying this weak miscellato the incoming-material in'group II in f the descending leg I of the conveyor-conduit I.

As illustrated, pure solvent is pumped by pump JS from storage tank l5 to a pure solvent-tank I5 located above the conduit-conveyor l to provide a suitable head. From this tank IS the .pure 'solvent is passed through a pipe I6, heater 1'! l and pipe I65 to branch inlet-conduits 18 which i connect with individual or independent inletconduits i2 connect'ed to'inlets in the conveyor casing at diffusion" sections or imperforate portions of said group ;9 in the outgoing leg l of 'said conveyorconduit where an extraction operation comprising alternate diffusion and leaching takes place. The flow of extraction liquid Y through these pipes may bejcontrolledor regulated by valves I2 -The used solvent fromgroup 9 is drained and 29 arranged on opposite sides of saidjinlet and having screen-portions 28' and 29' and jackets 28a and 28F, and thereafter draining the miscella through said jackets or drainingboxes 28 ,19 and conducting the same by pipes 30,

30atoa still-,not. shown.

It will be seen that I thus provide, in the descendingleg orflight of the conveyor, a fllter ing section preferably extending to opposite sides of the miscella inlet 21' and that this filtering section, inthis embodiment of my invention,

comprises an imperforate percolating portion 21 and draining portions or boxes 28 and 29* one ofj which extendsbelow aninlet andthe other of which is positionedfabove the same. The solvent in this case is fed throughethe inlet to provide, within the imperforate portion, a percolating action so'as to cause the solid materialto function as a filtering bed. Assuming that a flaked soy beans are fed through the material feed hopper 3i and moderately packed within the filtering section 26 andlparticularly within the imperforate portion, the soy-bean flakes will serve as' an efficient filtering agent or filter bed and when :miscella is percolated therethrough at material which had been; in suspension in the miscella.

As the deposit ofthe fines in the interstices'of' the soy-bean flakes in the conveyor section increases, the miscella will encounter :more resistance andif a hydrostatic head is em .throughscreens l3, boxes I4, pipe portions I!" a multiplicity of Suewhich the operation of filtering may be carried on without the necessity of providing any special apparatus therefor. The filtering operation is accomplished with fresh solid material and the feed of solvent is so regulated as to produce within the. imperforate portion of the filtering section a percolating action instead of a diffusion action, and such filtering operation may be carried on at any suitable position in a conveyor of the type hereinabove specified.

When a filtering action of the type specified is utilized in combination with the extraction apparatus hereinabove described, the liquid miscella to be filtered will be fed through the leg of the conveyor-casing into which the feed of 'solid material is delivered, and will, as aforesaid, percolate, leaving in the interstices of the packed flaked material the fine particles of solid material which had been in suspension in the miscella. The flaked material so loaded will then, in the same continuous conveying movement, be

' immediately conveyed to and through the extraction or alternate difiusion and leaching sections of. my apparatus.

Obviously, as the feeding process of solid material through the hopper continues, the whole column of fresh flaked material will be forced through the filtering section and the fresh material will serve as a filter bed in said section and, as the particles are heavily deposited, the material will be displaced and a new continuouslymoving filter bed of such material will pass into place, and a new coat of fines will be deposited in the interstices. In the apparatus shown, the fines deposited move downwardly. Consequently,

the path or line of least resistance for the miscells. will be upwardly, but a relatively small amount of liquid will, under pressure percolate I downwardly through the downwardly-moving material to a level below the miscella feed conduit to the perforated drainage section 2 9 while the main body of'miscella" liquid from the miscella feed conduit will follow the line of least resistance and move upwardly at a more rapid rate than that of the material toward the upper screen draining or outlet section whereit will pass through the perforations of the screened portion and into the drainag box 28. Miscella from both boxes is conducted through the pipes 28 and 29 to a still or to a suitable storage tank not shown. In some cases the perforate drainage section 29 may be omitted.

It will be obvious that the oil-bearing filtering material, after mi scella has passed through it,

will be soaked with solvent'and oil and will contain fine particles of the material in process, all of which are valuable, and that such solvent and oil as well as the oil-bearing fine particles will be automatically recovered in further processing in the extraction section. On the other hand, the miscella will be further enriched because it will dissolve the free oil contained in the flakes and this will provide a further separate economy in the distilling step of the extraction process.

After the travel of the material through the diiiusion agent or solvent, as hereinabove described, said material is preferably passed through an elongated draining section I the drained liquid from which ispassed through the pipe I2 into pipe I2 where it joins the solvent coming from the adjacent drain or percolating box of the group 9.. The percolated or drained material is then conveyed to a spout l and dropped by gravity into one of a group of dryers D and D'.

Owing to the fact that vapors passing from the dryers to the condensers always carry fine dust which impairs the efliciency of the condensers, it has been the practice in the art to interpose, between the dryers and the condensers, dust collectors of some type. In accordance with my invention, I avoid and eliminate such dust collectors. Thus, as shown, particularly in Figs. 1 and 3 to 5, I force the solvent vapors bearing dust through a layer of material LM. This is accomplished by positioning the vapor-outlet conduit I in relation to the discharge conduit l' and so as to provide an imperforate conveyor section l between such material discharge and said vapor outlet conduit. It will thus be seen that the vapors arising from the dryer are compelled to pass through a continuously-moving layer of solid material LM to reach the vapor outlet conduit I from which they pass to a suitable condenser C. In order to force the vapors to traverse the extraction material layer to the condenser, a seal should be built up in the spout or hopper 3| adjacent to the material inlet and in the embodiment illustrated, such a seal is produced by providing, in the spout or hopper 3!, a suitable depth of material which is continuously and at all times kept full of material. Such arrangement will also cause a condensation of solvent vapors in the material entering the extractor through the hopper 3l resulting in preheating the material and soaking it with solvent as it enters the extractor. In case-the material to be extracted is flaked or prepared under hot conditions, a conventional star feeder or an airlock positioned between the hopper and the extractor will provide the necessary seal.

In certain forms of dryers commonly used,.the solvent vapors are, in such dryers, superheated and when dryer devices of this type are employed in conjunction with my apparatus, a part of the superheated vapors will, by passing through the material layer LM, preheat the material just prior to its passage to the spout 3| and before the same enters the dryers.

Some solid materials will be more suitable than others for extraction in my aforesaid apparatus. The spacing of the percolating or draining boxes and the consequent length of the imperforate sections through which the solvent must pass will depend upon the characteristics of the material to be extracted. The coarser th material the less friction there will be and consequently the spacing of the percolating or draining boxes will be further apart and the imperforate diffusing sections will be longer. Theoretically, if it were possible to have a material which offered no resistance to a counter-current fiow of the solvent in a conveyor of the type specified arranged as in Fig. 1, there would be no need of percolating boxes but, inasmuch as that theoretical possi bility does not exist, my provision of percolating or draining boxes is designed to overcome the vvent to circulate injcounter-currentl friction which is encountered to compel the sol- , It'will be understood that if a solventof high specific gravityis employed. so that vthematerial hasf-a tendency ,to float, my apparatus will be equallysuited, to extract with. such solvent;

- In Figs. 3 and 4 I have showna horizontallydisposed construction embodying another application ormodification of my invention. In this embodiment of my invention, the solid material is fed continuously through hopper, 32 and of the tank to a horizontal leg 58' of aconventional conveyor-conduit having additional legs 58 and 158 extending abovepthe tank 51 and having a discharge connection or outlet chute 59 connected with one or a series of three dryers -50, 50, 605irom which the material may be, de-

{ livered to additional solvent-eliminating apparatus or to a storagebin. I The conveyor, as shown,

through'a material inlet or'feed hopper.32 into a horizontally-disposed conveyor'33 whichis of conventional,typeexceptmr applicatidn thereto of the draining boxes and the solvent :conducting pipesr In Figs, 3 and 4, the percolating sections w 34and 35 and the imperforate section 35 constitute a,filtering section such ashereinabove de-- l scribed, ,while theremaining drainingboxes 0011-, nected with the conveyorconstitute a series of extraction unitswhich are arranged in diffusion and leaching groups, which as illustrated, come prise groupsof three drainingtboxes or leaching H sections 3], 38 and -spaced fromeachbther to provide therebetween imperforate portions or dif fusionsections' 40,4l.; ReferringtoiFig. 4, pure g,

solvent is fed from a tank 42 through pipe 42 to inlet conduitst43, 43' which are connected with 'theiimperfora-te portionsor diiiusion sections 40 and 41;. Used solvent isdrainedfrom draining boxes 31-an d 3ii through -thepipe 44 into tank 45, irom which it is pumped by pump through conduit to and through inlet-branch and 36,, and conducted to a miscella storage tank forstill not shown. In, other'respects this constructionis similar tothat ,hereinabove shown,

and described in relation to Figs, 1 and 2.

3 In Fig. 5,"I haveshown a v modified embodi ment of my invention in which an extraction column or tank is combined with the conduit-conveyoi' extractioni apparatus of mypresent invention which, it will be seen, will have the double "function of conveying the process," mate,- rial from the extraction column or tank to the dryers and simultaneously extracting soluble ingredients" therefrom; One of the advantages of this newcombinationis that the extraction ooluinn'or tank of my former patents maybe substantiallyreduced in length or height. A combination-of this type, however, will be principally useful in the extraction ofmaterials which main- ,ly require a processof washing or leaching as is. of the chain type and'has a continuous connecting upper part 58, a descending empty leg 58 and a, connecting lower part 58', the entire conveyor being constructed in well-known vaportigh't sections and being supported by members 6|,. 5I', 6le andlwheel 62 journalled on shaft 82' rotated from any suitable source of power not shown, to move the chain of conveyors.

qIn' thelascending' leg 58 'of the conveyor above the'liquid-leVeI-SI in extraction column or tank 51, 1 provide a. group or series of alternate imperforate and perforate sections G3 and, the

latter of which is surrounded by liquid-draining boxes65 similar in all respects to the draining boxes hereinabove described.

- 7 In the instant embodiment of my invention,

pure :or ,fresh solvent is fed from tank 65 through conduit 61, heater 6B and conduit 61' into the leg 58 of the conveyor 58 at the upper part thereof and is caused to percolate downwardly through the upwardly-moving material in the 30" conveyor; As illustrated, solvent enters the conduitqat the imperforatesectionfl between the upper boxes and is drained from theseboxes and'from-the draining section 59 and conducted to a lowerimperforate section in substantially the imannerhereinabove describedin relation to Fig.1 until the solvent reaches the lowermost group of boxes which drain into pipe ,1 0 which conducts the solvent to the empty descending leg 58 -abovethe solvent level II in the conveyor.

The used solvent, therefore, passes through this descending leg and up through the materialout letopening SHinto the extraction tank 51 in counter-current with the material.

After passage through. the tank, the used solvent or miscella passes out through pipes-12 to a filter it 1 necessary, and then to a distiiler.'

It will be seen, therefore, that the materialand solvent, bothin the tank 51 and in the 0011-! veyor leg 58* move in counter-current relationship: that I have prOvided in the lower portion of. the conveyor a suitable, head of liquid "for forcing passage thereof through the tank. andthat I, have, in the conveyor, provided the drainingboxes and connecting pipes to overcome the frictionencountered by the solvent in passing through the material,as hereinabove moreparticularly described; e a

ThepperatiOn of, the various extraction units will be apparent tothose skilled in the art from the above description It will, be obvious alsothat inthe apparatus shown in; Fig. 5, the conveying movement of the distinguished from such"materi als as vegetable seeds which require washing or leaching and diffusion, r A I ,In the apparatus of Fig. 5, the material t be extracted-is fed through'hopper 55 and screw-; conveyor-conduit 56;to a vertically-disposed exmaterial and, the flow of the solvent passed through the inlet conduit 61 may be suitably regulatedin relationto'the quantity of solvent percolating through the perforations of, the perforated.

portions toproduce a washing or leaching action in the imperiorate sections of the leg 58 as well traction ,tank 5J, which maybe of my known,

type, but which preferably, as shown, is of the type illustrated and iully described in my Patents Nos 2,156,236 and 2,158,782. 5 The said material 4 fed. through thehopper'is passed througha process" oisolvent extraction in the tank andthenv conducted through an outlet 51f in the ,bottom b as in theperforate sections. This may be ac'com plished by so regulating the quantity and pressure of ,the ingoing solvent in relation to the quantity beingjdrain'ed as'to keep'solvent continuously flowing through the imperforate sections at a suitable rate without anyfilling of such imperforate sections.- A' -valve 6'! may be used to regulate the flow of the solvent from the tank 66. Obviously, by similar regulation of the regulating valves in the embodiments of my invention shown in Figs. 1-4, the quantity of solvent percolated may also be controlled so as to produce a washing or leaching action in the imperforate sections as well as in the perforate sections.

Having described my invention, I claim:

1. Counter-current solvent-extraction apparatus embodying, in combination, a conduitconveyor comprising a liquid and vapor tight conduit and liquid-passing conveyor members movable therethrough and adapted to carry solid material to be extracted, said conduit having material feed-inlet and discharge openings and being provided, between said inlet and discharge openings, with a plurality of perforate wall sections arranged .to cooperate with imperforate wall sections of the conduit to provide extraction sets, each set including at least one perforate and one imperforate section andlhaving a solventinlet pipe connected thereto, means for draining solvent from the perforate section, said conduitconveyor being of the continuous chain type having a plurality of legs and each leg being provided with a group of extraction sets arranged in successive relationshipqalong the length of the leg, means for conducting fresh solvent to the group in the leg nearest to the material discharge opening, and means for conducting enriched solvent from said last-mentioned group to a group nearer the material feed inlet, whereby the solvent and material 'will be moved in'counter-current relationship.

2. Counter-current solvent-extraction" appa ratus embodying, in combination, .a' conduitconveyor comprising a liquid and vapor tight conduit and liquid-passing conveyor members movable therethrough and adapted to carry solid material to be extracted, said conduit having material feed-inlet and'discharge openings and being provided, between said inlet and discharge openings, with a plurality of perforate wall sections arranged to cooperate with imperforate wall sections of the conduit'to provide extraction sets, each set including at least one perforate andone imperforate section and having a solvent-inlet pipe connected thereto, means for draining solvent from the perforate section, said conduit-conveyor being of the continuous chain type having a material-feed leg, an intermediate leg and a material discharge leg, each leg beingprovided with a group of extraction sets arranged in successive relationship along the length of the leg, and means for conducting fresh solvent to the group in the material-discharge leg, and means for successively conducting enriched solvent from said group in the material feed leg' to the group in the intermediate leg and from said intermediate leg group to the material-feed group, whereby the solvent and material will be moved in counter-current relationship.

3. Counter-current solvent-extraction apparatus embodying, in combination, a conduitconveyor comprising a liquid and vapor tight conduit and liquid-passing conveyor members movable therethrough and adapted to carry solid material to be extracted, said conduit having material feed-inlet and discharge openings, and

being provided, between said inlet and discharge openings, with a plurality of perforate wall sections arranged to cooperate with imperforate wall'sections of the conduit to provide extraction sets, each set including at least one perforate and one imperforate section and having a solventinlet pipe connected thereto, means for draining solvent from the perforate section, said conduit-conveyor having a-dryer connected with the material-discharge opening, a vapor-outlet conduit positioned adjacent to but separated from the said material discharge opening by a charged section of the conveyor, whereby vapors from the dryer are filtered through the solid material on their way to the vapor outlet.

4. Solvent-extraction apparatus embodying, in

to cause solvent vapors coming from said dryer 4 to traverse a bedof extracted material in the conveyor-extractor to filter said vapors.

5. A- process' of continuous solvent extraction of oil-bearing solid materials consisting in providing a continuous conduit-conveyor, feeding to and continuously moving solid material through said conduit-conveyor while maintaining the same in substantially filled condition to produce, in said conduit-conveyor, a columnar body of solid material having a given amount of frictional resistance to the flow of liquid-solvent, dividing, into a plurality of units, the total amount of friction in said columnar body by providing solvent outlets that divide said columnar body into a plurality of treating zones,

passing liquid-solvent through an inlet in each of said zones of said body of solid material during tional resistance to the flow of liquid-solvent, di-

viding, into a plurality of units, the total amount of friction in said columnar body by providing solvent outlets that divide said columnar body intoa plurality of treating zones, passing liquidsolvent in a sidewise direction through an inlet in each of said zones of said body of solid material during movement, regulating the rate of flow of said liquid-solvent to overcome the normal friction of the material encountered by the solvent, to compensate for the velocity of movement of such material and to provide for a fiood-. ing of said zones, and withdrawing used solvent from said zones through said outlets.

'7. A process of continuous solvent extraction of oil-bearing solid materials consisting in providing a continuous conduit-conveyor, feeding to and continuously moving solid material through said conduit-conveyor while maintaining the same in substantially filled condition to produce, in said conduit-conveyor, a columnar body of solid material having a given amount of frictional resistance to the flow of liquid-solvent, dividing, into a plurality of units, the total amount of friction in said columnar body by proof said zones.

- 8. A process of continuous solvent extraction 1 of oil bearing solid materials consisting in providing solvent outlets that divide said columnar body into a plurality of treating zones, Passing liquid-solvent in a sidewise direction through an inlet in each of said zones ofsaid body of solid material during movement thereof, regulating.

the rate of flow of the solvent to overcome the normal friction of the material encountered by the solvent, to compensate for the velocity of movement of such material and to provide for a flooding of said zones and an overflow at opposite ends thereof, and withdrawing used solvent through solvent outlets at opposite ends of each viding a continuous conduit-conveyor, feeding to and continuously moving solid material through said conduit-conveyor while maintaining the same in substantially filled condition to produce, in said conduit conveyor, a columnar body of solid material having a given amount of frictional resistance to the flow of liquid-solvent, dividing, into a plurality of units, the total amount of friction, in said columnar body by providing solvent outlets that divide said columnar, body into a plurality of treating zones, passing liquid-solventin a sidewise direction through an inletineach of said zones of said body of solid'm'aterial during movement thereof,

. regulatingthe rate of flow of said liquid-solvent to flood said lzones by overcoming the normal frictionpf thematerial encountered by the solvent, 'withdrawingused solvent from said zones "through said outlets, and applying the used solventnwlthdrawnflfrom one zone to a successive extraction zone in counter-current relationship to the movement of the solid material.

9. A process of continuous solvent extraction I ofoil-bearing solid materials consisting in providing a continuous conduit-conveyor, feeding to and continuously movingsolid material through said conduit-conveyor while maintaining the same in'substantially filled condition to produce,

in said conduit-conveyor, a columnar body of solid material having a, given/amount of fric- 'tional resistance to the flow of liquid-solvent, dividing, into a plurality of units, the total amount of friction in said columnar body by providing solvent outlets that divide said columnar body into a plurality of treating zones,

passing liquid-solvent in a sidewise direction through an inlet in each of said zones of said body of solid material during movement thereof,

, regulating the rate of flow of said liquid-solvent to flood said zones by overcoming the normal 7 friction of the material encountered by the solvent and compensating for the velocity of movement thereof, withdrawing used solvent from said zones through said outlets, applying the used solvent withdrawn from one zone to a successiveextraction zone in countercurrent relationship to the movement of the solid material, and repeating said process a plurality of times to subject the same moving column of material to a plurality of alternate stages of diffusion and leaching.

10. A process of continuous solvent extraction of oil-bearing solid materials consisting in providing a continuous conduit-conveyor, feeding to .and continuously moving solid material through said conduit-conveyor while maintaining the same in substantially filled condition to produce, in said conduit-conveyor, a columnar body of solid. material having a given amount of frictional resistance to the flow of liquid solvent,

dividing, into a plurality of units, the total amount of friction in said columnar body by providing solvent outlets that divide said columnar body into a plurality of treating zones, passing liquid-solvent in a sidewise direction through an inlet in each of said zones of said body of solid material during movement thereof, regulating the 'rate of flow of the solvent to overcome the nor mal friction of the material encountered by the solvent, to compensate for the velocity of movement of such material and to provide for a flooding of said zones and an overflow at opposite ends thereof, withdrawing used solvent through solvent outlets at opposite ends of each of said zones, and applying the used solvent withdrawn from one'zone to a successive extraction zone in counter-current relationship to the movement of the solid material.

11. A process of continuous solvent extraction of oil-bearing solid materials consisting in providing a continuous conduit-conveyor, feeding to and continuously moving solid material through said conduit-conveyor while maintaining the same in substantially filled condition to produce, in said conduit-conveyor, a columnar body of solid material havinga given amount of frictional resistance to the flow of liquid-solvent, dividing, into a plurality of units, the total amount of friction in said columnar body by,

providing solvent outlets that divide said columnar body into a plurality of treating zones, passing liquld-solvent'in a sidewise direction through an inlet in each of said zones of said body of solid material during movement thereof, regulating the rate of flow of the solvent to overcome the normal friction of thematerial encountered by 

